Boundary Layer Transition and Surface Roughness Effects in Hypersonic Flow
Abstract
Experimental studies are being conducted to examine the stagnation region heating in transitional flow over blunt nose tips; and the effects of surface roughness on the heat transfer and skin friction to hypersonic re-entry vehicles. Measurements have been made of the distribution of heat transfer and skin friction over sharp and blunted cones to a range of incidences for surface roughness of 0, 10 and 15 mils. These studies have been conducted at a local Mach number of 11.7 and Reynolds numbers based on model length of 30 x million, giving roughness Reynolds numbers from transitional to fully rough over the models. New calorimeter and thin film instrumentation was developed expressly for the rough wall heating measurements. The measurements indicated that while the roughness-induced augmentations in heat transfer and skin friction were less than would be predicted using theories based on low speed data for low R sub k's, close to the nose tip significantly larger augmentation factors were observed. The current studies suggest that significant compressibility effects may be present in hypersonic turbulent boundary layers over rough walls. The models and highly detailed heat transfer and pressure instrumentation have been completed for the stagnation point heating studies. A new and novel throat valve has been developed to eliminate the frangible mylar diaphragm which can cause particles and disturbances during flow establishment in the shock tunnel. The experimental studies are now in progress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1981
- Accession Number
- ADA098122
Entities
People
- Michael S. Holden
Organizations
- Calspan